1221365 has 8 divisors (see below), whose sum is σ = 1551960. Its totient is φ = 919552.

The previous prime is 1221299. The next prime is 1221373. The reversal of 1221365 is 5631221.

It can be written as a sum of positive squares in 4 ways, for example, as 303601 + 917764 = 551^2 + 958^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1221365 - 2¹² = 1217269 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7100 + ... + 7269.

It is an arithmetic number, because the mean of its divisors is an integer number (193995).

2^1221365 is an apocalyptic number.

It is an amenable number.

1221365 is a deficient number, since it is larger than the sum of its proper divisors (330595).

1221365 is a wasteful number, since it uses less digits than its factorization.

1221365 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14391.

The product of its digits is 360, while the sum is 20.

The square root of 1221365 is about 1105.1538354455. The cubic root of 1221365 is about 106.8928090656.

Adding to 1221365 its reverse (5631221), we get a palindrome (6852586).

The spelling of 1221365 in words is "one million, two hundred twenty-one thousand, three hundred sixty-five".